Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 200005
TWDAT
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Mon Mar 19 2018
Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.
Based on 1800 UTC surface analysis and satellite imagery through
2330 UTC.
...SPECIAL FEATURES...
...ATLANTIC OCEAN GALE WARNING...
The 30-hour forecast, starting at 19/1800 UTC, is for a cold front
to be along 31N80W 30N81W. Expect: N of 29N E of the cold front to
76W SW WINDS 25 to 35 knots. Seas 9 to 12 feet. The 48-hour
forecast consists of: the cold front along 31N71W 26N75W 22N79W.
N of 30N between 72W and 78W SW to W WINDS 30 to 35 knots. Seas
12 to 17 feet.
...GULF OF MEXICO GALE WARNING...
The 24-hour forecast, starting at 19/1800 UTC, is for a cold front
to be along 30N83W 18.5N93W. Expect: N of 25N E of the cold front
SW WINDS 20 to 25 knots with FREQUENT GUSTS TO GALE FORCE WITHIN
30 NM OF THE COAST FROM SUWANNEE FLORIDA TO PASCAGOULA
MISSISSIPPI. SEAS less than 8 feet. N of 26N W of the cold front
to 93W W to NW winds 20 to 25 knots with FREQUENT GUSTS TO GALE
FORCE WITHIN 30 NM OF THE COAST E OF PASCAGOULA MISSISSIPPI. Seas
less than 8 feet.
...MONSOON TROUGH/ITCZ...
The monsoon trough passes through the coastal sections of Sierra
Leone near 08N13W, to 06N15W and 03N21W. The ITCZ continues from
03N21W to 02N25W 03N40W, to 03N51W at the coast of Brazil.
Precipitation: isolated moderate to locally strong rainshowers, in
a disorganized pattern, are from 08N southward from 60W eastward.
...DISCUSSION...
GULF OF MEXICO...
As of 1500 UTC, a prefrontal trough has entered the NW Gulf of
Mexico. A cold front is just inland over Texas. Scattered showers
are along the front. Weak ridging extends from southeast Florida
to the north central Gulf, supporting light to gentle southeast
winds over most of the region. Radar imagery shows scattered
moderate convection over the NE Gulf and Florida N of 28N between
81W and 87W.
A ridge over the northern Gulf will shift E ahead of
a cold front moving off the Texas coast this afternoon. The
front will extend from the Florida Big Bend area to Veracruz
Mexico early Tue, just as a reinforcing push of cold air moves
off the Texas coast. The reinforcing cold air will strengthen
the front late Tue as strong winds and building seas develop
over the northern Gulf. The front will exit SE of the Gulf by
early Wed. Winds and seas diminish across the Gulf Thu and Fri
as high pressure follows the front across the northern Gulf.
CARIBBEAN SEA...
A pair of scatterometer passes confirmed a large area of fresh to
strong trade winds off Colombia, and a smaller area of strong
winds south of the Bay Islands off central Honduras. Seas are
reaching 8 ft off Colombia, but are generally 4 to 6 ft in the
eastern and central Caribbean and tropical north Atlantic, and 2
to 4 ft in the northwest Caribbean. No significant convection is
noted.
High pressure north of the region will support fresh
to locally strong trades across the south central Caribbean the
next several days. Winds will reach near gale force along the
NW coast of Colombia during the overnight hours. A weakening cold
front will pass through the Yucatan Basin late Tue night. A tight
pressure gradient ahead of the front will generate fresh to
strong E to SE winds off the central coast of Honduras through Tue.
Undersea volcano Kick em Jenny, north of Grenada near 12.18N
61.38W, is in a state of unrest. The government of Grenada advises
mariners to observe a 5 km or 3.1 nm exclusion zone around Kick
em Jenny. Please see www.nadma.gd for additional information.
ATLANTIC OCEAN...
Please see Special Features section for information on the
developing gale warning in the Atlantic.
A cold front is over the W Atlantic from 31N57W to 27N70W.
Scattered moderate convection is within 60 nm of the front. The
front will shift eastward and weaken through Tue. Farther south,
weak ridging is supporting gentle breezes west of 60W, with 4 to 6
ft seas in open waters east of 75W, due mainly to residual
northerly swell.
The next cold front will move off the coast late Tue, associated
with a deep surface low moving off the mid-Atlantic coast. The
supporting upper trough will become negatively tilted as it
emerges off the coast. This will interact with the Gulf Stream to
support scattered thunderstorms Tue night off the northeast coast
of Florida. In addition to the gales, strong westerly winds and
seas ranging from 8 ft to as high as 17 ft will prevail north of
27N and west of 60W into Wed night.
A 1028 mb high pressure is centered near 31N27W, supporting
gentle to moderate NE to E winds over the subtropics and moderate
to fresh trades in the deep tropics. An upper trough is noted
along 28W north of 05N, supporting a few small areas of modest
convection along the monsoon trough and ITCZ. Recent altimeter
satellite passes indicate seas are still 8 to 12 ft north of 05N,
likely in persistent long period NW swell.
A weakening cold front will move east across the
waters N of 27N and E of 70W tonight. S to SW flow will increase
off NE Florida tonight and Tue ahead of a stronger cold front
moving into the region late Tue. Winds will reach gale force north
of 28N Tue night through Wed night as the front moves east. Winds
and seas will diminish Thu as the front reaches from Bermuda to
the Windward Passage, then continues E and slowly weakens.
For additional information please visit
http://www.hurricanes.gov/marine
$$
MT